This project was designed to explore the social and affective growth of young children in the context of their expanding cognitive capabilities. Relations between prosocial behaviors and the ability to take another person's visual or social-emotional perspective were examined. Eleven tests of the child's comprehension of another's social or physical perspective were administered individually to 115 children between the ages of 3 and 7 1/2 years. In addition, prosocial interventions of each child were assessed in six experimental situations which provided the opportunity to help, share, and/or comfort. Analyses indicate that: (1) ability to take another's perspective significantly increases with age on every cognitive task; (2) when sex differences are present, girls are superior at perspective-taking; (3) there is a relation between physical and social perspective-taking, but only for 4 1/2- to 7-year-olds and only when assessment of each type of perspective is determined by multiple assessments; (4) the ability to make inferences about another's experience is not associated with the inclination to act on another's behalf.